Flexible tubing is used in many medical applications. The flexing of the tube permits contoured placement. In a medical context, flexible tubing is required for use in catheter devices to prevent damage when inserted into a body lumen. However, flexible tubing has a continuing problem with collapse. To prevent collapse, catheters require adequate stiffness to effect insertion into the body lumen and to resist collapse as the respective interior and exterior pressures of the tube vary.
Catheter tubes are typically used for nasogastric suction, for the administration of intravenous fluids and blood, for hemodialysis and other blood handling techniques, for gastro-duodenal feeding tubes, suction tubing, and tracheostomy tubing. Kinking of such tubing can cause blocking of the catheter. When kinking or suction induced collapse of the tube walls occur, flow ceases in the tubing and the consequences can be serious--even fatal.
Knotting can also occur in tubing induced into a body cavity. Such knots make it impossible to withdraw the tubing without resorting to surgery.
Catheters can be a source of infection. This problem is exacerbated the longer the catheter remains in the body. Organisms can enter the body at the skin surrounding the catheter or through the interior of the catheter.